DECATUR, Ga. (USA TODAY) - The Atlanta metro area briefly suffered the terror of another school shooting Tuesday, but the day ended in relief.

The suspect, Michael Brandon, 20, was in custody, accused of of firing an assault rifle at an elementary school in a confrontation that forced the evacuation of 800 or more students and prompted police to return fire.

A school office worker said she talked him into putting down his weapon.

No one was injured, school spokesman Quinn Hudson said.

DeKalb County Police Chief Cedric Alexander said the suspect fired at least a half-dozen shots with an assault rifle from inside the school, and officers fired back.

The shooting took place at Ronald E. McNair Discovery Learning Academy, a 5-year-old school named for an astronaut who died aboard Challenger, the space shuttle that exploded after takeoff in 1986.

The incident came as schools around the country are resuming for the fall academic calendar. Many districts took steps over the summer to improve security in light of the Newtown, Conn., shootings in December, when a 20-year-old gunman killed 20 children and six adults with a high-powered weapon before killing himself.

Alexander said the McNair school has a system requiring visitors to be cleared and buzzed in, and the gunman gained entry by slipping in behind someone authorized to enter. He said the man did not get past the school's main office.

School clerk Antoinette Tuff said she worked to convince the gunman to put down his weapons and ammunition.

"He told me he was sorry for what he was doing. He was willing to die," Tuff said in an interview on ABC's World News with Diane Sawyer.

She said she told him her life story, including about the end of her marriage after 33 years.

"I told him, 'OK, we all have situations in our lives," she said. "It was going to be OK. If I could recover, he could, too."

Tuff said she asked the suspect to put his weapons and backpack down.

"I told the police he was giving himself up. I just talked him through it," she said.

Assistant Police Chief Dale Holmes said the suspect was not injured and was undergoing police interrogation.

Hudson said all the students have been accounted for. Students were evacuated into a field behind the school and reunited with their parents at a nearby Walmart, Hudson said.

Television images from a helicopter showed the students racing out of the building, escorted by teachers and police.

A woman in the school office called WSB-TV as the events were unfolding. She said the gunman asked her to contact the Atlanta station and police. WSB assignment editor Lacey Lecroy said the woman who made the call said she was alone with the man and his gun was visible.

"It didn't take long to know that this woman was serious," Lecroy said. "Shots were one of the last things I heard. I was so worried for her."

DeKalb County Schools Superintendent Michael Thurmond praised faculty and authorities who got the students to safety, staying calm and following safety plans in place.